Journeyman 11 does NOT need a guess. Say C1R1 is bottom left row and column. Then you can fill in C5R7 because of the 6 in row 7. That means C5R10 must be an X, otherwise there would be a chain of 4 in C5. Now, if row 10 had a 3 to the left of this X, then C2R10 and C3R10 would be filled in. This would mean that C2R9 would be filled in, but C3R9 would be an X, which is impossible as row 9 has a 3 in it. So, the row 10 3 must be to the right of the X in C5R10. Then you can fill in C8R10. Easy from there.
Walkthrough for Final level, build a wall to route the creeps up and along to the far right. Near the entrance, build a 3x3 square of boosters surrounding a fully loaded sniper. Max out the boosters' damage, and as much cash multiplier as possible. The sniper will have >10k damage! Then, as the cash accumulates, build rightwards a ladder of boosters surrounding snipers, so that each sniper has 8 boosters around it. Each sniper should share 3 boosters with its neighbour. Max out these shared boosters first, as both snipers benefit. Use raw boosters to route the creeps all the way back left again, but always maxing out the leftmost sniper/booster combos first. Keep increasing the booster and sniper stats as the cash comes in. At the bottom, make a switchback all the way to the right to slow up the creeps. Enjoy the balloons!
Walkthrough for Bottleneck. Keep collecting money and swapping towers with the aim of getting two fully upgraded snipers just to the left of the hole. Bolster these snipers with five boosters to the left and below them. Make a maze in the right hand half to bring any stranglers back in range of the snipers. A wall from the bottom leftmost square straight up to nearly the top and then along towards the middle wall was in my map to divert the creeps.